Bryan Rust and Reilly Smith scored 41 seconds apart as the Pittsburgh Penguins scored four straight goals in a 5-2 victory at PPG Paints Arena.
Rust scored twice, Jake Guentzel had a goal and two assists, Evgeni Malkin and Smith each had a goal and an assist and Alex Nedeljkovic made 34 saves as Pittsburgh won its second straight game.
"I thought we were stiffer on the puck in the third", said Penguins head coach Mike Sullivan. "We just made better decisions on the entries. We ended up scoring off that opening draw. We got a lot of juice off that, for sure."
Matt Coronato scored his first NHL goal for Calgary and Jonathan Huberdeau had the Flames other goal while Jacob Markstrom made 25 saves.
"The hard part is we had a good first two periods, played a good solid road game to start. You let momentum get away from you", said Calgary head coach Ryan Huska.
"Whether we let it get away or we kind of gave it to them, however you want to put it, it happened."
Penguins explode in third, pull away from Flames for second consecutive victory
After neither team scored over the first 38:21 of the game, Coronato broke the deadlock, blasting a one-timer form the bottom of the left faceoff circle with the Flames on the power play.
"I think it's kind of hard to think about it the way we came out and played in the third", he said. "I think we just didn't do a great job managing pucks.
"Couple, maybe, mental mistakes that we'll definitely clean up. It's important stuff. We'll have to get better."
Rust tied the game 18 seconds into the third period after Kris Letang sent a shot off the end boards, gathered in the loose puck and wristed off the right post and in.
Smith, acquired from defending Stanley Cup champions Vegas on June 28, scored for the second straight game 23 seconds later, shooting from the slot off a cross-ice feed from Malkin.
Guentzel increased the lead, scoring for the first time this season on a one-timer from the right circle set up by Letang.
"It feels good", Letang said. "We had a couple chances. Missed an easy one in the first. It's nice to be able to get one and, hopefully, it snowballs from here."
Malkin made it 4-1, taking a drop pass from Smith and beat Markstrom under the blocker. He has six points (two goals, four assists) in three games so far.
The goal was his 473rd in the NHL, tied with Alexander Mogilny for third-most by a Russian-born player behind Alexander Ovechkin (522) and Sergei Fedorov (483).
"I didn't think about that", he said. "I try to catch Ovechkin maybe, but it's not easy. I did my best. I hope when i'm retired, I look back and say I did for myself and just, right now, I don't think about points or anything. Just do my best."
Huberdeau cut the lead in half with a backhander with 3:55 remaining.
"We can't let up against a team like that", he said. "A couple mental mistakes that we had in the third. They took advantage of that. I thought, overall, our work ethic was great tonight.
"We worked hard. It's just some mistakes that kind of turned the puck into our net."
Rust scored into the Calgary empty net with 22 seconds to play for the 5-2 final.